Single-stage cold start and evaporative control method and apparatus for carrying out same

ABSTRACT

As cold start is initiated in a spark-ignition internal combustion engine, lower molecular weight constituents of a fullrange gasoline are selectively eluted by an elution system including an adsorbent bed of adsorbent material. The adsorbent bed forms an elution zone within a cannister assembly in fluid contact with the full range gasoline. The adsorbent materialusually in pelletized form- is preferably housed within a tubular means disposed within the cannister assembly, the tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a controller circuit. A vapor emission control system can also be housed within the cannister assembly and undergo selective operation to prevent escape of vapor emission originating from within the carburetor and gasoline tank.

United States Patent Csicsery [11] 3,831,572 Aug. 27, 1974 [75] Inventor: Sigmund M. Csicsery, Lafayette,

Calif.

[73] Assignee: Chevron Research Company, San Francisco, Calif.

22 Filed: Oct. 4, 1972 21 Appl.No.:295,028

[52] US. Cl 123/179 G, 123/3, 123/127, 123/180 R [51] int. C1. lFQZm l/16, F02m 27/02 [58] lFieid 01 Search. 123/179 G, 3, 180 R, 187.5 R, 123/119 E, 127

Primary Examiner-Charles J. Myhre Assistant Examiner-W. H. Rutledge, Jr.

Attorney, Agent, or Firm-R. L. Freeland, Jr.; H. D. Messner [57] ABSTRACT As cold start is initiated in a spark-ignition internal combustion engine, lower molecular weight constituents of a full-range gasoline are selectively eluted by an elution system including an adsorbent bed of adsorbent material. The adsorbent bed forms an elution zone within a cannister assembly in fluid contact with the full range gasoline. The adsorbent material-usually in pelletized form-is preferably housed within a tubular means disposed within the cannister assembly, the tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a controller circuit. A vapor emission control system can also be housed within the cannister assembly and undergo selective operation to prevent escape of vapor emission originating from within the carburetor and gasoline tank.

10 Claims, 8 Drawing Figures PATENTEDAUBZ'IISM mum? PATENIEDmszmn ,amaia I Y III/II PATENTED m9 2 majors 1 SINGLE-STAGE COLD START AND EVAPORATIVE CONTROL METHOD AND APPARATUS FOR CARRYING OUT SAME RELATED APPLICATIONS Applications filed simultaneously with the subject disclosure which are assigned to a common assignee and containing common subject matter, but claim distinct inventions, include:

The present invention relates to cold starting and evaporative emission control of a spark-ignition internal combustion engine and has for an object the provision of a simple and effective cold start and evaporative control system for use in such engine i. for selectively eluting from a full-range fuel flowing to the engine only the lower molecular weight constituents at cold start so as to allow quick starting of the engine without excessive amounts of unburned hydrocarbons appearing at the exhaust as well as ii. for adsorbing evaporative emissions from the gasoline tank and carburetor bowl when the engine is not operating.

Higher molecular weight constituents adsorbed during cold start and/or light, evaporative emissions adsorbed during the disabled cycle of the engine are purged from the system only after the engine has been warmed and the full range fuel utilized.

During cold start of spark-ignition internal combustion engines, the fuel-air ratio is generated by the airfuel intake system, say a conventional carburetion system. At cold start, the air-fuel ratio can be varied (enriched) to assure adequate amounts of lower molecular weight constituents of the fuel at the intake manifold. By operation of a plurality of interrelated wellknown parts, the lower molecular weight constituents become more easily vaporized to form combustible vaporfuel/air ratios to allow starting of the engine even at low operating temperatures. However, since remaining higher molecular weight constituents are not oxidized even if the start is rapid, such remaining constituents contribute to the formation of unburned hydrocarbons at the exhaust Although a more volatile fuel having a lower boiling point, would permit faster starts and warmup and reduce exhaust pollutants, including unburned hydrocarbons and carbon monoxide emissions, experience shows that full range engine performance using the more volatile fuel would be adversely affected; In this regard, fuel consumption would be greatly increased over all ranges of driveability.

In accordance with the present invention, rather than use a more volatile fuel under a multiplicity of operating conditions of a spark-ignition internal combustion engine (particularly during cold start), lower molecular weight constituents of a full-range gasoline are selectively eluted as cold start is initiated by the driver. The elution system includes an adsorbent bed of adsorbent material, preferably of the polar type, for example, silica gel, forming an elution zone within a cannister assembly in fluid contact with the full range gasoline. The adsorbent material-usually in pelletized form-*is preferably housed within a tubular means disposed within the cannister assembly, the tubular means being positioned within a much larger shell housing in fluid contact with a valve and conduit network. Entry of the gasoline is initiated by the valve and conduit network under control of a controller circuit.

Construction of the cannister assembly can vary. Preferably the arrangement resembles that provided for a shell-and-tube heat exchanger whereby tube-side gasolineduring cold staitpasses through the tubular means packed with the adsorbent material (single pass percolation). Selective retardation of the higher molecular weight compounds, vis-a-vis the lower components occurs so that, during start up, the latter constituents pass to the fuel well of the carburetor, and thence mixed with air in a preselected air-fuel ratio for later consumption within the combustion chambers of the engine. Since the starting cycle of an internal combustion engine is quite short, say from 1 to 15 seconds and the residence time for the high molecular weight compounds within the elution zone is l to 2 orders longer say from 1 to 3 minutes, theheavier compounds remain selectively adsorbed with the elution zone.

Preferably, but not necessarily, the present invention has additional utility in preventing evaporative emissions originating within the fuel well of the carburetor and/or within the gasoline tank for escaping into the atmosphere. In this aspect of the invention, the escape of large amounts of hydrocarbon fumes and vapors into the atmosphere from a spark-ignition internal combustion engine in an inoperative state, is acknowledged as being a serious environmental problem, especially within large cities. In this regard, studies indicate that up to 15 percent by volume of the total vapors admitted into the atmosphere, originate from evaporative emissions from spark-ignition internal combustion engines. Governmental bodies are attempting to satisfy emission regulation in cooperation with industry; for example, California Motor Vehicle Pollution Control Board has proposed the following standards for control of evaporative emissions: 2 grams per hot soak from the carburetor fuel well and 6 grams per day from the fuel tank under standard operating conditions. In this regard, the present invention can be selectively, but not necessarily, operative during such time periods to adsorb such evaporative emissions and prevent their escape into the atmosphere by arranging the cannister assembly so as to provide an annular space between the tubular means and the shell housing. Into the annular space can be inserted an adsorbent material, preferably of the nonpolar type, which form an adsorptive capture zone for use in preventing escape of evaporative emissions into the atmosphere when the engine is in an inoperative state.

The associated valve and conduit network and the controller circuit can place both the elution and capture zones of the cannister assembly in fluid contact with other relevant fuel system components as required; for example, after the engine has started and warmed up both the elution and capture zones can be purged of adsorbed constituents (adsorbates) by passing shell-side gases (either full or partial engine air or manifold exhaust gases) through these zones. Thus, not only is the present invention able to rapidly elute low molecular weight fuel constituents at cold startup, but the other adsorbed fuel components can be automatically desorbed without formation of excessive amounts of pollutants at the exhaust.

Although the prior art has suggested both polar and non-polar adsorbent materials for use in vapor recovery systems, there has been no suggestion of using adsorbent materials in an elution system for selectively eluting from a full-range gasoline, only light, low molecular weight components thereof, to assure a smooth pollution-free start of a spark-ignition internal combustion engine.

Further objects, features and attributes of the present invention will become apparent from a detailed description of several embodiments to be taken in conjunction with the following drawings in which:

DESCRIPTION OF THE FIGURES FIG. 1 is a schematic view of a portion of an engine fuel system incorporating the present invention illustrating a typical carburetor and air cleaner assembly interconnected between a cold start evaporative emission system of the present invention, said cold start evaporative control emission system including a cannister assembly housed within the air intake line of the air cleaner assembly under regulation of a valve and conduit networks controlled by a controller circuit;

FIG. 2 is a partial cutaway of the cannister assembly of FIG. 1;

FIG. 3 is a sectional view taken along line 33 of the cannister assembly of FIG. 2;

FIG. 4 is a schematic view of another embodiment of the present invention illustrating a typical carburetor and air cleaner assembly in which the cannister assembly is mounted by means of a platform attached to the fire wall of the engine compartment;

FIG. 5 is a plan view of the cannister assembly and air cleaner assembly of FIG. 4;

FIG. 6 is a fragmentary view of the valve and conduit network of FIGS. 1 and 4 illustrating the position of the valve network after cold start has been achieved and the engine is at running temperature so that the cannister assembly can be desorbed by passing gases in heat transfer contact therewith:

FIG. 7 is a partially schematic view illustrating an alternate embodiment by which air can be heated to an elevated temperature to better desorb the cannister assembly of FIGS. 1 and 4;

FIG. 8 is yet another fragmentary view of the valve and conduit network of FIGS. 1 and 4 illustrating the position of the valve network when the engine is in an inoperative state.

Referring now to FIG. 1, there is illustrated an engine fuel system 10 connected to an engine intake manifold 11 of a spark-ignition internal combustion engine (not shown). Fuel system 10 of the present invention includes an air intake system 12, a carburetor 13, a fuel intake system 14, that includes cold start-evaporative control system 15 of the present invention.

To form a combustible air-fuel mixture, air enters by way of air intake system 12, say by way of air inlet line 16a, and is filtered at an air filter interior of an air filter housing 16c, before entry into carburetor 13. Carburetor 13 includes choke and throttle valves 17 and 18, respectively, a fuel well 19, and a discharge nozzle 20. Fuel well 19 contains a metered quantity of gasoline to be mixed with air passing discharge nozzle 20. The resulting fuel-air mixture passes through intake manifold 11 into the engine combustion chambers (not shown) where combustion occurs. Supplying fuel well 19 with a metered quantity of gasoline is by means of fuel intake system 14. Fuel intake system 14 includes a gas tank 23 containing a reservoir of full-range fuel (i.e., a full-boiling gasoline), a fuel pump 24 and cold startevaporative control system 15 of the present invention. Cold start-evaporative control system 15 includes a valve and conduit network 25 in fluid contact with the discharge side of fuel pump 24 but under operative control of controller circuit 26. A cannister assembly 27, see FIG. 2, mounted adjacent to the air intake system 12, say within air inlet line 16a, is also an element of the cold start system 15. Valve and conduit network 25 of FIG. 1 is seen to include cold start inlet and exit valves 25a and 25b, respectively, controlled mechanically by relays means 26a of controller circuit 26 through transducer 26d and electrically through bimetal temperature switch 26b, ignition switch 260 and battery 26f. A second relay 262 of controller circuit 26 is seen to control operation of evaporative emissions control valve 25c of valve and conduit network 25 through mechanical transducer 26g. Transducers 26d and 26g convert rectilinear travel of the relay means 26a and 26e to rotational motion.

COLD-START EVAPORATIVE CONTROL SYSTEM 15 As indicated with reference to FIG. 1, during cold start of a spark-ignition internalcombustion engine, a full-range fuel, i.e., a full-boiling gasoline, having high and low molecular weight constituents, is conveyed from gas tank 23 through fuel pump 24 into valve and conduit network 25, and thence from cannister assembly 27, (FIG. 2) to fuel well 19 of the carburetor 13. Although a full-boiling gasoline enters the cannister assembly 27, in accordance with present invention, only light molecular weight liquid constituents are eluted into the carburetor 13 for mixing with air to form the cold start air-fuel mixture. Such selective retardation during the initial one-three minutes of the starting cycle of the internal combustion engine of the heavy molecular weight vis-a-vis light groups is achieved based on the functional characteristics of an elution zone 28 formed within the cannister assembly 27. Since the nature of the elution zone 28 is based on the functional characteristics of adsorbent materials in general, a brief discussion of adsorbtion systems is believed to be in order and is presented below with reference to FIG. 2.

Essentially, interior tubular means 31, located within a much larger shell housing 32, forms a column of a solution adsorbtion, frontal analysis chromatagraph as classified in accordance with Kirk-Othmer Encyclopedia of Chemical Technology, Second Ed., Volume 5, page 418. In accordance with Kirk-Othmer op. cit., such classification is essentially based on the nature of the mobile phase of the system precolating through an absorbent material. In the case at hand, fullboiling gasoline enters by way of inlet conduit 33 and percolates through adsorbent material 34 packed within the tubular means 31. Note at the outlet conduit 36, the order of elution is a function of the order of polarity of the constituents of the full range gasoline since the individual molecules of the heavy molecular weight constituents within the tubular means 31 shuffle at a slower rate between the mobile and stationary phases than do the lighter constituents. Thus, within elution zone 28, separation is believed to occur, inter alia, because of polarity, nonpolarity characteristics of the constituents whereby different relative velocities are imparted to the individual molecules of the groupings. The least strongly adsorbed low molecular weight components elute as a group at the outlet conduit 36 first, followed by a second grouping containing say both the light and heavy molecular weight constituents and so forth until all constituents have appeared.

Residence time of the lighter components within the elution zone 28 is a function of many factors including the length of the tubular conduit means 31 as well as the pressure drop during perculation through the adsorbent material 34. However, the residence time of the heavier components is much longer, ranging from 13 minutes. However, care ought be exercised in this regard. The flow rate of the mobile phase must be slow enough to allow maximum transfer of the molecules of the heavier constituents into and from the stationary and mobile phases. Since selective retardation of the heavier constituents due to relative polar-nonpolar interaction between the heavier components versus the adsorbtive material 34, is quite long, say 1-3 minutes, while the typical starting cycle of a modern engine can be quite short, say from 1 second up to seconds (except when problems of starting occurs), the heavier constituents remain adsorbed within the tubular means 31 after the engine has started, assuming, of course, that the adsorbent material 34 constituting the elution zone 28 is of a compatible classification.

CLASSIFICATION OF ADSORBENT MATERIAL 34 As previously mentioned, competition for the. heavier molecular weight groupings of the full-range fuel is believed to be, more or less, dependent on its selective polar interaction with the adsorptive material 34. The degree of interaction (between material 34 and the more polar heavier molecular weight constituents of the full-range fuel) is believed to be directly related to the magnitude of the polarity of the former. In accordance with the present invention, then adsorptive material 34 is preferably formed of a polar material, say one selected from the following nonexclusive listing of popular polar adsorptive materials with silica gel being somewhat preferred:

Barium sulfate Calcium carbonate Glass Resins and plastics Quartz Titanium dioxide Ion-exchange only -Continued Polar Adsorptive Materials Remarks Metallic oxides Zeolites (sieves) Sil X Solid Support Materials Coated Commonly used in liquid liquid with Liquid adsorbers, partition chromatography preferably chemically bonded (Eg. Durapak, Solids Coated with Octadccyl Silnne,

Fluoro-cthers).

Adsorbent material 34 can be formulated in a convenient form for use within the cannister assembly 27. For example, the elution zone 28 can be formed of adsorbent material in granular, pelletized or powdered form. Preparation is straight forward: the adsorbent material should be calcined, acid and base washed, neutralized, and size graded prior to insertion within tubular means 31, say along lines set forth in Kirk- Othmer, op. cit., Volume 1, page 460. Since as previously mentioned, the flow rate of the full range gasoline within the elution zone must be slow enough to allow maximum transfer of the molecules of the heavier compounds into and from the stationary and mobile phases, the size of the adsorbent material 34 should be such as to minimize the pressure drop across a cannister assembly 27 without adversely affecting its ability to adsorb the heavier constituents. In this regard, an elution zone 28 having about a l-liter capacity filled with activated alumina of 8 by 14 mesh has been found to adsorb from 200-300 ml. of aromatic constituents while yielding about 400 to 500 ml. of light molecular weight constituents in the first initial minutes of the cold starting operation. In addition to activated alumina, it has been found that polar gels, such as silica gel, titania gel, zirconia gel, and alumina gel, as well as Fullers earth, bentonite, diatomaceous earth, forisil, attupulgus, and any other polar adsorptive materials are also useful in carrying out the present invention. However, in some cases, it should be noted that nonpolar materials may also be used, although less advantageously, within the elution zone 28. Nonpolar materials listed hereinafter appear to be quite useful under such circumstances.

CANNISTER ASSEMBLY 27 Construction of the cannister assembly 27 varies with the type of mounting required to attach the cold start evaporative control system 15 adjacent to air intake system 12. In FIG.'2, cannister assembly 27 is seen to be mounted within the intake air line 16a of the air intake system 12. The overall diameter of the cannister assembly 27 thus must be minimum so as to allow sufficient air to bypass into the carburetor 13. To accomodate the required volume of adsorbent material constituting the elution zone 28 (FIG. 2), the tubular means 31 may have to be correspondingly ultra-long. Support of the ultra-long tubular means 31 can be brought about by welding radial supports 37 to the side wall of air line 16a to which cold start conduits 33, 36 as well as evaporative conduit 38 are attached. Support rings 40 and 41 are attached at respective ends of the tubular means 31. Each ring 40 and 41 has a peripheral edge in contact with the shell housing 32. Each ring 40, 41 also includes a central plug zone in plugging contact with the central tubular means 31 as well as an intermediate zone 43 (See FIG. 3) including a series of ports 44 in registry with an annular spacing existing between tubular means 31 and the shell housing 32 wherein adsorbent material 45 is supported. Adsorbent material 45 located in the aforementioned annular space constitutes a vapor adsorption zone, generally indicated at 46 (adsorption capture zone). In this aspect of the invention, deactivation of ignition switch 260 (of FIG. 1) deactivates relay 26e causing rotation of the vapor control valve 25c to the position shown in detail in FIG. 8. The fuel well 19 and the gas tank 23 of FIG. 1 are thus placed in fluid contact with the vapor adsorption zone 46. Note that at the shell side exterior of the central tubular means 31, within zone 46, the atmosphere is permitted to enter and leave at'will. During cold start, since the shell-side air is at about the same temperature as the fluid interior of the tubular means 31, little heat is transferred between the two fluids.

In FIG. 4, the support of the cannister assembly 27 differs markedly from that of FIG. 1. The cannister assembly 27 of FIG. 4 is seen to be mounted by shell housing 50 to a platform 51 which in turn is attached to a firewall (not shown) of an engine compartment. Additional space afforded by the platform 51 allows for a more complex constructural design of the cannister assembly 27. Instead of constructing tubular means 31 of a single tube as depicted in FIG. 1, a series of upright tubular means 52 can be provided to carry the gasoline entering inlet chamber 53 along a series of sinusoidal passes through the interior of the cannister assembly 27, such passageways resembling those provided in a conventional tube-and-shell heat exchanger. The series of sinusoidal passes made by the gasoline are indicated by solid arrows 54 while the dotted arrows 54 indicate the direction of the gas phase flow. In the depicted arrangement, tube-side gasoline is conveyedduring cold starting-through the tubular members 52 between the inlet and exhaust chambers 53 and 55 respectively (multipass percolation) through adsorbent material 56 packed within the tubular members 52. Due to increased total length of the tubular members 52, the resulting elution zone 57 is likewise greatly enlarged over that depicted in FIG. 2. Since the absolute length of the cannister assembly of FIG. 4 can be correspondingly reduced. Not only does the effluent at the exhaust chamber 55 consist essentially of high molecular weight constituents during the cold start cycle, as previously explained but also the heavier constituents remain adsorbed within adsorbent material 56 until long after the engine has warmed up. This is to say, because the heavier constituents are retarded during percolation through the elution zone 57 for a longer time than required to usually start the engine, the effluent within the carburetor per each starting cycle internal combustion engine is limited essentially to the lightweight constituents.

Further constructural differences between the embodiments depicted in FIG. 1 and FIG. 4 are readily apparent. For example, in FIG. the shell housing 50 is seen to be rectangular in cross-section whereby the assembly forms a parallelepipedon. Also, the shell housing 50 is also seen to include end walls 58 and 59. Each end wall 58 and 59 includes a series of ports 60 to allow selective entry of hot, exhaust gases into an adsorptive vapor capture zone generally indicated at 61 exterior of tubular member means 52 but interior of shell housing 50. Within the vapor capture zone 61, adsorbent material 62 is supported. End wall 58 is also seen to attach by way of fasteners to the air cleaner housing 160. Such attachment is oriented such that the ports 60 are in registry with aperature 16d of the air cleaner housing 160. End wall 59 is seen to be connected to a conduit 64 having a remote end (not shown) connected to a source of exhaust gases, say the exhaust manifold of the engine.

Of course tubular members 52 need not be discontinuous so as require the use of intermediate chamber 65 (FIG. 4) to reverse the flow of the mobile phase; e.g., the tubular members 52 can be U-shaped with remote ends in fluid contact with inlet and exhaust chambers 53, 55, respectively.

Although the embodiment depicted in FIG. 1 utilizes full or partial engine air warmed to a high temperature for this purpose, it should also be noted that the embodiment of FIG. 4, contemplates utilization of gases from the exhaust manifold to purge with the elution and vapor adsorption zones of adsorbed constituents; e.g., after the engine has started and warmed, the inlet and outlet cold start valves 25a and 25b can assume the positions depicted in FIG. 6 so as to utilize full-range fuel within the fuel well 19. Simultaneously with the utilization of the full-range gasoline, the elution zone of the cannister assembly 27, as well as the vapor zones within the fuel well 19 and gas tank 23, can be placed in fluid contact with the carburetor 13 by operation of exhaust start valve 25b and evaporative control valve 25c. I.e., the elution zone can be connected via conduits 36, 91 and 92 (connected by respective ports of the valve 25b of FIG. 6) to the carburetor 13; the fuel well 19 via conduit 83 and valve 25c can be also placed in fluid contact with the conduits 91 and 92, as can the gas tank 23 via conduit 84 and valve 250. In that way, as desorption of the heavier compounds occurs, say as warmed gases are conveyed in heat transfer contact with the elution zone, and these compounds are swept into the carburetor 13, there can be a simultaneous conveyance of evaporative emissions, if any, from the fuel well 19 and gas tank 23 to the carburetor 13. With the desorption of the compounds within the elution zone and the fuel well and gas tank, it should also be pointed out that vapors captured within the adjacent absorptive capture zone of the cannister assembly can likewise be purged. However, instead of the desorbed materials entering the carburetor below the air intake system, the captured evaporative emissions pass directly into air intake system 12 and thence to the carburetor l3.

In FIG. 4, the conveyance of the hot exhaust gases from the exhaust manifold is under control of additional electrical circuitry (not shown) of the controller circuit 26. When the temperature of the exhaust manifold reaches a selected temperature, a relay (not shown) is tripped to pass the purging gases through the cannister assembly 27 of FIGS. 4 and 5 via conduit 64. The desorbed materials within the elution and vapor adsorption zones of the cannister assembly 27 are ultimately consumed within the combustion chambers of the engine.

Where the heavier compounds within the elution zone of the cannister assembly 27 have relatively high boiling points, too high in fact to be renewed by passing adjacent engine air in heat transfer contact with the elution zone, the embodiment depicted in FIG. 4 is especially useful. In this regard, the adsorbent material 56 of FIG. 4 can be renewed using the hot exhaust gases as the purging agent. If the temperature of such exhaust gases range from 700 F. to about 800 F., only a relatively short desorption time is required. Temperatures of the adsorbent bed comprising the elution zone can be a range from 400-500 F. with about 450 F. being a satisfactory operating temperature.

Generally desorption time is quite short for such range setting, say being from about 2-12 minutes in duration. The resulting desorbed compounds then pass through the air intake system and carburetor 13 to the combustion chambers where they are consumed.

Capture of evaporative emissions within vapor adsorption zones of the cannister assemblies 27 of FIGS. 2 and 4 can also be desorbed utilizing the purging gases in the manner described above. It should be noted that the captured adsorbates within the vapor capture zone are mostly light molecular weight constituents. Accordingly, the adsorbent material indicated at 45 in FIG. 2 and at 62 in FIG. should be nonpolar. In this regard, the following nonpolar adsorbent materials are pre' ferred in carrying out this aspect of the present invention.

Nonpolar Adsorbent Material Remarks Organic only Metallic only Even though the cannister assembly 27 of FIG. 4 is larger than that depicted in FIG. 2, it provides better heat transfer characteristics during desorption of the elution and vapor adsorption zones since the available heat transfer area (between the heat transferring media) is much larger. That is to say, the shell-side hot gases traveling through the cannister assembly 27 of FIG. 4 is in heat transfer contact with a multiplicity of the tubular member means, not just a single tubular means as in FIG. 2. Also, since temperature of the gases is much higher, the total purge time is greatly reduced. In this regard, the total flow rate of the hot purged gases at the air intake system should be carefully controlled so that the composite temperature of the inlet air to the carburetor is not too hot for efficient utilization of the resulting air fuel mixture within the combustion chamber of the engine.

FIG. 7 illustrates yet another mode for desorbing the elution and vapor adsorption zones of the cannister assembly of FIGS. 2 and 4. In accordance with the illustrated embodiment, engine air is heated by passing the air adjacent to exhaust manifold 70 and thence through the cannister assembly where desorption occurs.

In more detail, the exhaust manifold. 70 is provided with an exterior hood 7] having lower skirts 72 which snuggly tit adjacent to the exhaust manifold, yet are open to incoming air. A central register 73 is also provided with a nozzle 74. Nozzle 74 in turn is attached by flexible conduit 75 connected at a port 76 say at the air intake line 16a of the air intake system of the embodiment of FIG. 2. At the air intake line 16a, a solenoid operator 77 is positioned so that damper 78 is in register with port 76. Opening the damper 78 allows warmed engine air to enter the cannister assembly (not shown).

SEQUENCE OF OPERATIONS Reference should now be had to FIGS. 1, 2, 46, and 8 illustrating the method aspects of the present invention. In more detail, it should be apparent that the initiation of the cold start cycle automatically occurs when the driver closes ignition switch 26c of the controller circuit 26 of FIGS. 1 and 4. Before the driver engages the ignition switch 260, however, the valve and conduit network 25 and particularly the evaporative control valve 25c is in the position illustrated in FIG. 8 to carry out the vapor adsorption control function of the present invention. That is to say, the evaporative 3-way control valve 250 is in a relaxed state so that its exhaust port 80 and inlet ports 81 and 82 are in fluid communication with fuel well 19 of the carburetor 13, and to the gas tank 23, respectively, say via conduits 83 and 84. When the engine is in an inactive state, and evaporation of the fuel occurs, the vapors pass through conduits 83 and 84, 3-way control valve 25c and conduit 38 to the vapor adsorption zone of the cannister assembly 27 of FIGS. 2 and 4. Adsorption of the vapor prevents its escape into the atmosphere.

Prior to initiation of cold start, assume the fuel well 19 has been emptied of full-range fuel. In this regard, consider also the function of drain conduit 85 of FIGS. 1 and 4 connected between fuel 'well 19 and gas tank 23. When the engine is in an inactive state, fuel within the fuel well 19 (liquid phase) drains therefrom via conduit 85 to the gas tank 23. As shown, the conduit 85 is provided with an oriface 86 so as to control the rate of drainage of the fuel, say at a rate which will allow total removal of all fuel from the well within a 6-l2 hour period. Thus, when the engine is parked overnight, the drain conduit 85 in cooperation with orifice 86 provide for total removal of full range fuel from the fuel well 19. It should also be apparent that if the drainage conduit 85 is mounted at the sidewall of the fuel well (not at the bottom wall as shown) not all of the full range fuel will be drained. Instead, a residual reservoir remains, the amount of which is a function of the connector position relative to the top wall of the fuel well, e.g., if the connector to the fuel well and conduit is at a location say about two-thirds of the way away from the top wall, the residual fuel would be onethird of the total fuel well capacity. During initial starting of the engine, the position of nozzle 20 of the carburetor 13 could be arranged, depthwise, so that a selected, compatible mixture of the residual and eluted fuel would enter the carburetor to effect cold start of the engine.

As the engine turns over, the fuel pump 24 conveys full-range fuel through inlet start valve 250 to the cannister assembly 27 of FIGS. 2 or 4. Within the cannister assembly 27, the full-range fuel percolates through the elution zone culminating in the elution of parafiinic components at fuel well 19. Aromatic components of the full-range fuel remain adsorbed. From the fuel well 19, a metered amount of the parafiinic components is conveyed via nozzle 20 into the carburetor 13 where the fuel and air are properly mixed and then convey for consumption within the combustion chambers of the engine. After selected rise in the engine temperature, as measured by bimetal switch 26b of the controller circuit 26, say positioned at the water jacket or exhaust manifold of the engine, control relay 26a becomes deactivated, resulting in the cold start inlet and exhaust valves 25a and 25b returning to relaxed positions as shown in FIG. 6.

After the cold start exhaust and inlet valves 25a and 25b return to relaxed positions depicted in FIG. 6, the fuel intake system switches over to full utilization of the full-range gasoline. That is to say, fuel conveyed from fuel pump 24 passes via conduit 87 to inlet valve 25a and thence from U-shaped conduit 88 and exhaust cold start valve 25b to the fuel well 19. As full-range fuel is used, the elution zone of the cannister assembly is placed in fluid contact with the carburetor.

It should be pointed out that during the operation of the engine, the evaporative control valve 25c of the valve and conduit network 25 remains in an activated state as depicted in FIGS. 1, 4 and 6. However, when the driver opens the ignition switch 260 of the controller circuit 26, the evaporative control valve 25c is likewise deactivated which places it in the position depicted in FIG. 8 whereby the vapor adsorption zone of the cannister assembly 27 is in direct fluid contact with the fuel well 19 and gasoline tank 23. In that way, as evaporative emissions are formed within the fuel well 19 or the gasoline tank 23, they are conveyed via conduits 83 and 84 respectively through inlet ports 81 and 82 and exhaust port 80 and conduit 38 to the vapor adsorption zone.

While the certain preferred embodiments of the invention have been specifically disclosed above, it should be understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the an and thus the invention is to be given the broadest possible interpretation within the terms of the following claims.

I claim:

1. Apparatus for reducing exhaust and inoperative pollutants produced by a spark-ignition internal combustion engine of the type including an air intake system, fuel intake system, and a mixing means interconnected therebetween for mixing full-range fuel with air to form a combustible mixture for delivery to combustion chambers of said engine, comprising:

i. a cannister assembly containing adsorbent material (a) capable of selectively adsorbing high molecular weight constituents of said full-range fuel at cold start while eluting substantially unimpeded a coldv start fuel effluent composed essentially of only low molecular weight constituents as well as (b) capable of selectively absorbing vapor constituents of said full-range fuel during an inoperative state of said engine,

ii. valve and conduit network means attached between said cannister assembly, a reservoir means for said full-range fuel and said mixing means for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means and said mixing means, said network means including a first plurality of conduit and valve means including first and second valve means controlling flow relative to said cannister assembly so as to allow, (a) in a first operating state, flow of said full-range fuel from said reservoir means to said cannister assembly and flow of said cold start fuel effluent from said cannister assembly to said mixing means to provide for rapid starting of said engine without producing excessive exhaust pollutants and, (b) in a second operating state, fullrange fuel to flow directly from said reservoir means to said mixing means bypassing said cannister assembly after said engine is in a normal running condition, said network means also including a second plurality of conduit means including a third valve means operatively connected between said cannister assembly said fuel reservoir means and said mixing means for selectively conveying vapor evaporative emissions of said fuel within said fuel reservoir and/or said mixing means to said cannister assembly, when said engine is in said inoperative state,

iii. control means operatively connected to said first, second and third valve means of said valve and conduit network for changing operation states so as to direct fuel flow relative to said cannister assembly, said reservoir and mixing means as a function of one or more engine operating parameters.

2. Apparatus of claim 1 in which said mixing means includes a carburetor having a fuel well, and a bore in registry with said air intake system, said fuel well of carburetor being in selectively liquid contact with said cannister assembly and said reservoir means through said first plurality of conduit means including said first and second valve means, said first valves means being positioned between said reservoir means and an inlet of said cannister assembly and having first and second operating states for controlling flow of full-rangefuel between said reservoir means relative to said cannister assembly and said second valve means, said second valve means being positioned between said fuel well and an outlet of said cannister assembly also having first and second operating states coextensive in time with said operating states of said first valve means for controlling flow of said full-range fuel and said cold start fuel effluent relative to said fuel well as a function of engine temperature.

3.'The apparatus of claim 2 in which said fuel well and said reservoir means are placed in selective vapor contact with said cannister assembly through said second plurality of conduit means including said third valve means as a function of a selective engine parameter indicative of said inoperative state in said engine whereby evaporative vapor emissions from said fullrange fuel within said fuel well and said reservoir means can be conveyed to said cannister assembly for adsorption therein thereby preventing escape into atmosphere surrounding said engine.

4. Apparatus of claim 3 in which said cannister assembly includes an elongated tubular means disposed within an enlarged shell housing to form a shell-andtube arrangement for conduction of tube-side and shell-side fluids in adjacent but independent flow relationship, said tubular means including a central segment supporting a first bed of adsorbent material forming an elution zone for eluting low molecular weight cold start fuel, and separate inlet and outlet means connected to said reservoir and said carburetor, respectively, through said first and second valve means, so as to selectively deliver fuel to said fuel well of said carburetor as a function of a selected engine parameter, said shell housing including a central portion forming a second bed of adsorbent material open at one end to atmosphere surrounding said engine and at another end connected to said bore of said carburetor so as to guide at least a part of the intake air of said air intake system to said carburetor, and an entry vapor conduit means connected to said reservoir means and said fuel well of said carburetor through said third valve so as to allow selection vapor contact therebetween as a function of a selected engine parameter indicative of the inoperative state of said engine whereby evaporative emissions can be absorbed within said second adsorbent bed and do not escape into said surrounding atmosphere.

5. Apparatus of claim 4 in which said elongated tubular means includes a singular tubular conduit arranged within a single tubular shell housing, said single tubular conduit arranged to rigidly support said first bed of ad sorbent material therein but having radially extending inlet and outlet conduit means in contact with first and second valve means respectively so as to allow only single pass flow of said full-range fuel relative to said shell housing during cold start of said engine.

6. Apparatus of claim 4 in which said tubular means is a multiplicity of tubular conduits each arranged parallel to each other within a single tubular shell housing, each conduit supporting a segment of said first bed of adsorbent material but all terminating at central inlet and outlet chambers in operative contact with said first and second valve means, whereby full-range fuel percolating therethrough during cold starting of said engine is provided with a multiplicity of sinusoidal paths within said single enlarged tubular shell housing.

7. Apparatus of claim 4 in which said adsorbent materials within said first and second adsorbent beds are of different polarity classification.

8. Apparatus of claim 7 in which said first adsorbent bed is formed of a polar adsorbent material while said second adsorbent bed is formed of a nonpolar adsorbent material.

9. Apparatus of claim 4 in which said one end of said shell housing is not open to the atmosphere surrounding the engine but is connected by air intake control means including conduit means to a source of heated gas, so as to allow selective flow of said heated gas through said cannister assembly for purging both first and second beds of adsorbed fuel constituents, said purged constituents from said first and second beds being carried into and consumed within said combustion chambers of said engine during normal running operation.

10. Apparatus of claim 4 in which said air intake system includes an air cleaner assembly having an air intake line and an air filter, said air intake line including support means for rigidly supporting said cannister assembly in flow relationship with said bore of said caburetor. 

2. Apparatus of claim 1 in which said mixing means includes a carburetor having a fuel well, And a bore in registry with said air intake system, said fuel well of carburetor being in selectively liquid contact with said cannister assembly and said reservoir means through said first plurality of conduit means including said first and second valve means, said first valves means being positioned between said reservoir means and an inlet of said cannister assembly and having first and second operating states for controlling flow of full-range fuel between said reservoir means relative to said cannister assembly and said second valve means, said second valve means being positioned between said fuel well and an outlet of said cannister assembly also having first and second operating states coextensive in time with said operating states of said first valve means for controlling flow of said full-range fuel and said cold start fuel effluent relative to said fuel well as a function of engine temperature.
 3. The apparatus of claim 2 in which said fuel well and said reservoir means are placed in selective vapor contact with said cannister assembly through said second plurality of conduit means including said third valve means as a function of a selective engine parameter indicative of said inoperative state in said engine whereby evaporative vapor emissions from said full-range fuel within said fuel well and said reservoir means can be conveyed to said cannister assembly for adsorption therein thereby preventing escape into atmosphere surrounding said engine.
 4. Apparatus of claim 3 in which said cannister assembly includes an elongated tubular means disposed within an enlarged shell housing to form a shell-and-tube arrangement for conduction of tube-side and shell-side fluids in adjacent but independent flow relationship, said tubular means including a central segment supporting a first bed of adsorbent material forming an elution zone for eluting low molecular weight cold start fuel, and separate inlet and outlet means connected to said reservoir and said carburetor, respectively, through said first and second valve means, so as to selectively deliver fuel to said fuel well of said carburetor as a function of a selected engine parameter, said shell housing including a central portion forming a second bed of adsorbent material open at one end to atmosphere surrounding said engine and at another end connected to said bore of said carburetor so as to guide at least a part of the intake air of said air intake system to said carburetor, and an entry vapor conduit means connected to said reservoir means and said fuel well of said carburetor through said third valve so as to allow selection vapor contact therebetween as a function of a selected engine parameter indicative of the inoperative state of said engine whereby evaporative emissions can be absorbed within said second adsorbent bed and do not escape into said surrounding atmosphere.
 5. Apparatus of claim 4 in which said elongated tubular means includes a singular tubular conduit arranged within a single tubular shell housing, said single tubular conduit arranged to rigidly support said first bed of adsorbent material therein but having radially extending inlet and outlet conduit means in contact with first and second valve means respectively so as to allow only single pass flow of said full-range fuel relative to said shell housing during cold start of said engine.
 6. Apparatus of claim 4 in which said tubular means is a multiplicity of tubular conduits each arranged parallel to each other within a single tubular shell housing, each conduit supporting a segment of said first bed of adsorbent material but all terminating at central inlet and outlet chambers in operative contact with said first and second valve means, whereby full-range fuel percolating therethrough during cold starting of said engine is provided with a multiplicity of sinusoidal paths within said single enlarged tubular shell housing.
 7. Apparatus of claim 4 in which said adsorbent materials within said first and second adsorbent beds arE of different polarity classification.
 8. Apparatus of claim 7 in which said first adsorbent bed is formed of a polar adsorbent material while said second adsorbent bed is formed of a nonpolar adsorbent material.
 9. Apparatus of claim 4 in which said one end of said shell housing is not open to the atmosphere surrounding the engine but is connected by air intake control means including conduit means to a source of heated gas, so as to allow selective flow of said heated gas through said cannister assembly for purging both first and second beds of adsorbed fuel constituents, said purged constituents from said first and second beds being carried into and consumed within said combustion chambers of said engine during normal running operation.
 10. Apparatus of claim 4 in which said air intake system includes an air cleaner assembly having an air intake line and an air filter, said air intake line including support means for rigidly supporting said cannister assembly in flow relationship with said bore of said caburetor. 